1. Field of the Invention
The present invention relates to chain continuously variable transmissions.
2. Description of the Related Art
Continuously variable transmissions (CVTs) are known in which two pulleys each have opposing conical surfaces and each are configured so that the distance between the conical surfaces can be changed, and a flexible endless member is wound around the two pulleys. Rotation of one of the pulleys is transmitted to the other pulley via the flexible endless member. At this time, the running radius of the flexible endless member around each pulley is changed by changing the distance between the opposing conical surfaces, whereby the change gear ratio can be changed.
CVTs using a chain as the flexible endless member are known in the art. In this chain, plate-like links each having an opening are arranged in the circumferential direction of the chain. The chain is formed by coupling chain elements to each other. Each chain element includes a link unit and two pins. The link unit is formed by a plurality of the links arranged in the lateral direction of the chain. The pins extend through both ends of each of the openings of the links. The chain elements are coupled to each other by inserting the pin of each chain element through the openings of the links of another adjoining chain element.
Both ends of both or one of the two pins of each link unit contact the opposing conical surfaces of the pulley. European Patent Application Publication No. 1862700 (EP 1862700) discloses a chain in which a contact point of a pin with a conical surface of a pulley is located outside the centerline of the pin in the thickness direction of the chain (see FIG. 3B). EP 1862700 describes that positioning the contact point in this manner can reduce noise (see FIG. 5).
Loss that is caused by slipping at the contact point of the pin with the pulley has not been considered in the chain CVTs.